Study On Extraction And Purification Of Lentinan And Its Molecular Structure Modification

The chemical and physical properties of lentinan and its molecular structure were summarized, and the biological activities and mechanisms of the immunal modulation, antitumor,antivirus and antibacterial were discussed, the main motheds of measurement and analysis for lentinan were listed , the relationships between structure and effect of lentinan were studied, meanwhile , some ways of molecular modification for lentinan were studied.An economic and efficient technics was established by studying lentinan extraction, purification and abstraction. The main process is as follow:1, In the method of extraction by water and alkali, Orthogonal test was carried out in this paper, the result showed as follow: adding distilled water at 80: 1 ratio by volume, water bath at 94℃ for 12h, then extracting lentinan by alcohol at 6: 1 ratio by volume. Among three factors, the alkali concentration had the largest influence on caustic solubile lentinan, the best concentration was determined 1M.2, Single factor enzymolysis experiments made clear about their effects on lentinan extraction. 60 min enzymolysis time, and previous pH5.5 during 40℃ were the best for the result, while the amount of enzyme had little effect on lentinan extraction. Single-factor enzymolysis experiment offered essential data standard to followed multiple-factor enzymolysis orthogonal test.3, Lentinan extraction technics were studied in the multiple-factor enzymolysis orthogonal test, the best lixiviation technics was as follow: adding 1% protein multi-enzyme, setting previous pH as 6.0, heating at 40℃ water bath for 100min, and extracting lentinan by water after protein multi-enzyme been inactivated4, The content of the water extraction lentinan was 47.83%, and it became 86.96% after Sevag deprotein process. The Ultraviolet Spectrum showed that there wasn't protein, nucleicacid because no absorb peaks at 260nm and 280nm.By the infrared spectrum, the molecular structure was determined as β-D-glucan.The molecular structure of lentinan and its molecular modification were studied, and the lentinan with 0.34 million Dolton average molecular weight was obtained.Lentinan was sulfated by the means of Wolfrom,sulfuric acid and triethylamine-Sulfur trioxide, respectively, and the infrared Spectrum results showed that method of Wolfrom which had higher proportion of sulfate substitution was a ideal way. The 13C-NMR data showed that the sulfates were located on the carbon-6 in sulfated derivative of lentinan.Carboxymethyl derivative of lentinan was prepared. Its degree of substitution was 0.5. The infrared spectrum showed carboxymethyl group absorption peaks and characteristic absorption peaks of P -D-glucan. The 13C-NMR spectrum confirmed that hydroxides on C-6 in the glucose residue of lentinan were substituted by carboxymethyl group.